Hovercraft questions

What is a hovercraft?
A hovercraft is a vehicle which is suspended upon a cushion of air.

Where and why are hovercraft used?
Hovercraft are used throughout the world as specialized transports

What are the alternatives to hovercraft and where are they used?

hovercraft accidents are amazingly difficult to find reports of. Doing searches on hovercraft and accidents invariably yields results on how hovercraft are used as rescue vehicles after other type of craft have an accident.
Since a couple of rail options are proposed as alternatives to using hovercraft in the Washington D.C. area

What is the history of hovercraft design and applications?
In 1710 Swedish scientist Emanhuel Swedenborg first mention the principles behind hovering and hoverboats. Austrian Dagobert Muller built teh first air-cushion vehicle in 1915

What are some of the most recent hovercraft developments?
For a while Ross is working on a real Workhorse Hovercraft to replace the Mustang design. This new craft has several innovations included which will provide safer crafts which will run more efficient for commercial applications.


A published article of a recent event concerning hovercraft


As so many Famous events and People were Born, Lived and worked in Portsmouth over the centuries I thought it would be a good idea to tell the story of the invention of the Hovercraft in 1955.

The idea of using an air-cushion as a means or aid to acceleration and reduction in (hydrodynamic) drag was first explored by Sir John Thornycroft, a British engineer, who, in the 1870's built some experimental models on the basis of an air cushion system that would reduce the drag of water on boats and ships.

In 1877 he successfully patented the idea and his theory was that if a ship's hull was given a concave bottom, which could be filled - and replenished - with air, it would create significant additional lift. And so the air cushion effect was born.

Decades later scientists and inventors were still busy with his ideas but without any practical applications. With the coming of the airplane however, it was noticed that additional lift was obtained if the plane flew closer to land or water, creating a "funnel effect", a cushion of air.

The air lift that this funnel effect created differed with the type of wing and its height above ground. The effect was strongest if this height was between one half and one third of the (average) front-to-rear breadth of the wing. Also known as "chord".

The next two decades saw little interest in air cushion development.

The successful use of the air cushion effect was not lost on engineers after World War 2 was over and in the early 1950's British, American and Swiss engineers started to rethink Sir John Thornycroft's problem.

The Englishman Christopher Cockerell, commonly seen as the father of the hovercraft, being retired from the army, settled into boat building where he soon got captivated by Thornycroft's problem of reducing the hydrodynamic drag on the hull of a boat by using some kind of air cushion.

His theory was that, instead of using the plenum chamber - an empty box with an open bottom as Thornycroft had devised - air was instead pumped into a narrow tunnel circumnavigating the entire bottom, it would flow towards the center and form a more effective air cushion. This peripheral jet would cause the air to build up enough pressure to equal the weight of the craft and, as it would have nowhere to go, the pressure would force the craft up, clearing it off the ground altogether.

Cockerell successfully tested his theory and filed his first patent in 1955. The year after he formed a company called Hovercraft Ltd. He further envisioned and partially worked out other problems of the hovercraft principle that still have to be fully exploited by modern hovercraft builders. One of these was to re-use the air for greater overall efficiency.

Thinking that his air cushion vehicles would be eminently suitable as amphibious craft he approached the British Ministry of Supply, the government's defence equipment procurement authority with his findings. Soon after, in 1956, the air cushion vehicle was classified as "secret" and a construction contract was placed with a British aircraft and seaplane manufacturer. The result was the SR.N1 in 1959.

The first SR.N1 weighed four tons and could carry three men. Its maximum speed was 25 knots (1 knot = 1.15 miles or 1.85 kilometres per hour) on calm water. It had a 6-inch (15 cm) rubberized skirt to make it easier to contain the air cushion on uneven ground.

Significant wear and tear of the skirt through friction with the water at high speeds made it necessary to use more durable material and a rubber and plastic mixture was developed by 1963. The length of the skirt had also been extended to about 4 feet (1.2 m).

Early interest in hovercraft enjoyed a peak in the early 1960's as everyone jumped to take advantage of this amazing vehicle. However, by the end of the decade only the British had produced a range of feasible and practical craft.

The problems inherent of the air cushion vehicle, such as Cockerell and others had foreseen, regarding steering control, noise, salt and skirt erosion, caused many countries to abandon their hovercraft development programs in favour of other, more established multi-function vehicles or to use different vehicles specialised in each terrain or function.

Since the 1970's however, and especially over the last decade, a renewed interest in the hovercraft as (passenger) transport, military transport and weapons carrier and exploratory vehicle has taken ground, solving many of these problems in their development.

Technology in general made large steps forward during the past twentyfive years, enabling organisations and governments, as well as many enthusiasts at Hovercraft Clubs to enjoy the hovercraft vehicle in its many forms including the very popular Remote Control model size hovercraft!.
work cited page www.articlesbase.com/


What is the environmental impact of hovercraft?
For any vehicle to operate economically the drag, or resistance to motion, must be kept to a minimum. The majority of drag arises from the motion of the vessels hull through the water, therefore we can reduce drag and consequentially propulsive power by minimizing hull contact. The hovercraft achieves this by using low-pressure air to form an air cushion beneath it, thus actually lifting the hull clear of the water. In addition, by using air propulsion to generate forward movement, the hovercraft becomes amphibious, and able to traverse land, soft terrain or water.



How have hovercraft impacted society?
In inventions and bad wheater,water and sand


Who:Christopher Cockerell
What:Born June 4 ,Cambridge United KIngdom, He then entered Cambridge University as an undergraduate member of Peterhouse, and where he studied engineering and was tutored by William Dobson Womersley.
What:Cockerell's greatest invention, the hovercraft, grew out of work he began in 1953. He tested his theories using a hair-dryer and tin cans and found his working hypothesis to have potential, but the idea took some years to develop, and he was forced to sell personal possessions in order to finance his research. By 1955, he had built a working model from balsa wood and had taken out his first patent. Cockerell had found it impossible to interest the private sector in developing his idea, as both the aircraft and the boat-building industries saw it as lying outside their core business. He therefore approached the British Government with a view to interesting them in possible defence applications.
Where:United Kingdom
Why: interested and curious
Money:he had enough
impact:A prototype craft was crossing the English Channel between Dover and Calais. Cockerell was knighted in 1969 for his services to engineering.